Additive manufacturing may be used to quickly and efficiently manufacture complex three-dimensional components layer-by-layer, effectively forming the complex component. Such additive manufacturing may be accomplished using polymers, alloys, powders, solid wire or similar feed stock materials that transition from a liquid or granular state to a cured, solid component.
Polymer-based additive manufacturing is presently accomplished by several technologies that rely on feeding heated polymer materials through a nozzle that is precisely located over a substrate. Parts are manufactured by the deposition of new layers of materials above the previously deposited layers.
In general, additive manufacturing selectively adds material in a layered format enabling the efficient fabrication of incredibly complex components. Unlike subtractive techniques that require additional time and energy to remove unwanted material, additive manufacturing deposits material only where it is needed making very efficient use of both energy and raw materials. This can lead to significant time, energy, and cost savings in the manufacture of highly advanced components for the automotive, biomedical, aerospace and robotic industries.
In fact, additive manufacturing is a manufacturing technique in which it may be faster, cheaper, and more energy efficient to make more complex parts. However, wide scale adoption of this technology requires a non-incremental improvement in production rates and component scale without sacrificing resolution.
Currently available fused deposition manufacturing (FDM) systems produce parts with high resolution (small deposition nozzles) but at low throughput or they produce parts with low resolution (large deposition nozzles) and high throughput. It is very desirable to achieve both high resolution and high throughput of material on a FDM system. This could be accomplished by equipping the FDM system with nozzles of selectable diameter. The small diameter would be employed at the part boundaries where high resolution is required and the large diameter nozzle employed for low resolution infill. It is also desirable that these nozzles share the same polymer delivery system and have the same centerline. Low additional mass is also desirable where the deposition head is required to execute high acceleration motion.
As such, it is desirable to maintain a controlled application of material onto the deposit surface. A single nozzle with a large orifice may result in a fast build with high throughput of material but with beads of material that are too large with poor resolution in the resulting build. A single nozzle with a small orifice may result in good resolution but poor throughput resulting in slow builds.
The subject invention improves the deposition quality and speed of additively manufactured parts by coaxially adjusting the nozzle orifice during deposition. The subject invention is further designed to include multiple deposit configurations including a stop configuration.